python solution 123456789101112131415161718192021222324252627 class (object): def subsetsWithDup(self, nums): """ :type nums: List[int] :rtype: List[List[int]] """ """ 思路整理:DFS recursion 1)对nums进行排序以避免nums中重复元素…

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining. For example, Given [0,1,0,2,1,0,1,3,2,1,2,1], return 6. The above elevation map is represented by a…

最长回文子串: 1. 暴力搜索   时间复杂度O(n^3) 2. 动态规划 dp[i][j] 表示子串s[i…j]是否是回文 初始化:dp[i][i] = true (0 <= i <= n-1);  dp[i][i-1] = true (1 <= i <= n-1); 其余的初始化为false dp[i][j] = (s[i] == s[j] && dp[i+1][j-1] == true) 时间复杂度O(n^2),空间O(n^2) 3.  以某个元素为中心,分别…

Problem 2 --- Add Two Numbers 简单的模拟题. Problem 3 --- Longest Substring Without Repeating Characters 题意: 给定一个字符串序列,找出最长无重复的子序列.如"abcabcbb"的最长不重复子序列为"abc" 思路: 首先分配一个hashTable[256],里面保存每个字符在当前字符序列中的位置,同时设置left变量表示当前无重复字符串的最左端位置.然后从头到尾扫面字符串…

Here is my collection of solutions to leetcode problems. Related code can be found in this repo: https://github.com/zhuli19901106/leetcode LeetCode - Course Schedule LeetCode - Reverse Linked List LeetCode - Isomorphic Strings LeetCode - Count Primes…

描述: Given an array of integers, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2. Please note t…

描述:Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using extra space. You could a…

描述:Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority element always exist in the array. 思路1:Moore voting algorith…

2. Add Two Numbers You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. Input: (2 -> 4 -> 3)…

Given an unsorted integer array, find the first missing positive integer. For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2. Your algorithm should run in O(n) time and uses constant space. 题意: 给定了一个无序数组,要求找到第一个缺失的正整数.如1,2,4,5的第一个缺失的正整数是3.要求时…